IQ, Claudius: lead pollution fuelled cognitive decline in Europe at peak of Roman empire

"Apart from the sanitation, the medicines, education, wine, public order, irrigation, roads, the fresh water system and public health, what did the Romans ever do for us?", asks Reg in Monty Python's Life of Brian.

- Ian Sample

One answer, according to a new study, is cognitive decline across Europe, courtesy of the vast quantities of lead pollution churned out by the booming metals industry that shaped the empire.

Researchers have said the expansion of mining and the processing of metal ores caused airborne lead pollution to soar during the peak of the empire, leading to an estimated drop in IQ of between 2 and 3 points.

"It's amazing that we were able to quantify atmospheric air pollution over Europe nearly 2,000 years ago and assess potential health impacts on the ancient Roman civilisation," said Dr Joseph McConnell at the Desert Research Institute in Reno, Nevada.

"Our findings demonstrate that anthropogenic emissions from industrial activities have resulted in widespread damage to human health for over two millennia, which is pretty profound in my view," he added.

Roman physicians were aware of the dangers of lead poisoning, but the metal was still widely used for water pipes and cooking pots and found its way into medicines, cosmetics and toys.

The metal was also ingested on purpose after Romans discovered that syrups containing lead helped to preserve and sweeten wine.